Personas provide a multi-dimensional method of targeting. They’re based, as the name suggests, on a projected persona for each customer ‘type’. Get it right, and personas can help you enormously in both predicting behaviour and personalising your communications. Personas are a powerful technique, and they’re increasingly used to improve the usability and customer centricity of communications.
It is vital to consider the questions that a customer will be answering - the information they will be seeking – at each stage of their journey because your email campaign should provide the answers. If a customer leaves an item in their online basket and they don't complete the purchase, send a personalised basket abandonment email including that very item:

If you don’t know the conversion rates on your optin page, then setup split testing. I recommend Leadpages for setting up your optin pages because they have built-in click tracking, A-B split testing, and they let you drive unlimited traffic. Of course, they have some beautiful optin page templates that you can edit very easily using their click-click interface.